LS35THa DX 35mm f/11.4 solar refractor package

by Lunt Solar Systems Print

What would you like to print?
(Reviews and Documents/Videos will not be printed)

Basic Product Information
Full Description
Tech Details
Supplied Accessories
Recommended Accessories

More product information
The Lunt LS35THaDX 35mm solar refractor and accessory package puts serious Hydrogen-alpha solar viewing within the reach of virtually every astronomer. You can piggyback this lightweight (3 pound) solar scope on a larger existing telescope or mount it on a photo tripod or altazimuth mount to use as a quick grab and go scope for spur-of-the-moment observing at lunchtime or when on vacation. Because this Lunt scope is small and compact (only 16.35” long and 62mm in diameter at its widest), the LS35THaDX is ideally suited to being mounted in pairs side by side for binocular viewing.

The H-alpha filter in the Lunt 35mm Deluxe solar refractor shows you much more of the living Sun than ordinary glass or Mylar white light solar filters that only show you sunspots. With the economical Lunt LS35THaDX Deluxe package, you see the violent ever-changing tapestry of multiple prominences leaping off the edges of the solar disk, as well as sunspots and some surface detail.

The Lunt LS35THaDX is based on a fully multicoated 400mm focal length achromatic refractor with a 35mm clear aperture and an f/11.4 focal ratio. Its built-in Hydrogen-alpha solar filter is centered on the 6562.8 Ångstrom H-alpha solar emission line. The filter has a narrow <0.75 Ångstrom passband for high contrast. The two-part filter uses a permanently mounted 35mm etalon behind the objective, with a 6mm blocking filter built into the standard equipment 1.25” star diagonal.

A tuning mechanism built into the system lets you tilt the etalon to center the passband precisely on the H-alpha line for maximum contrast. The tuning mechanism also lets you perform off-band observations of Doppler-shifted disk features to determine whether they are moving towards you or away from you.

The 6mm clear aperture of the H-alpha blocking filter in the star diagonal is matched to the focal length of the telescope for both visual observing and solar imaging. It gives you a full disk image of the Sun at prime focus with almost any 1.25” eyepiece you might care to use. The diagonal’s 1.25” eyepiece holder has a built-in helical focuser that makes focusing easy, even if you are observing in the dead of winter while wearing gloves or mittens. Simply rotate the eyepiece to focus it sharply on the solar image.

The LS35T Deluxe package comes with a 10mm 1.25” Lunt Solar eyepiece. This eyepiece has a wide 70° apparent field of view, giving you a magnification of 40x and a 1.75° actual field. This gives you plenty of dark sky background around the solar disk to show off the prominences. In addition, you can use virtually any other 1.25” eyepiece you might have with this 35mm Lunt solar refractor. A typical 20mm 1.25” Plössl will give you a magnification of 20x and a little over a 2.5° field of view compared with the 0.5° diameter disk of the Sun. A 6mm Plössl will give you 67x magnification and about a 0.77° field, letting you get up close to the Sun, although the resulting very narrow 0.52mm exit pupil may start dimming the prominence detail more than you might like to see.

To make lining up on the Sun easier and safer, a TeleVue Sol-Searcher non-magnifying pinhole finder is mounted on the LS35T optical tube. The Sol-Searcher has two small circular plates spaced 2” apart. A hole in its front plate projects an image of the Sun onto a circular white panel on the back plate. To use the Sol-Searcher, simply stand off to one side of your scope with your back to the Sun. While observing the position of the Sun’s image on the Sol-Searcher’s back plate, adjust the position of your LS35T until the Sun’s image falls on the circular white panel on the back plate. Once it does, your LS35T is pointing at the Sun. It’s that simple.

In addition to the Sol-Searcher finder, the Lunt LS35THaDX package comes with mounting rings that have collimation screws so you can precisely line up the scope with the optical axis of any larger scope on which it might be piggybacked. The rings are attached to a Vixen-style dovetail with 1/4”-20 thread holes that will let you mount the scope directly on a photo tripod for a quick peek at the Sun. 

You can also mount the scope’s dovetail directly onto any altazimuth or German equatorial mount that accepts a Vixen-style dovetail for easier extended observing and tracking of the Sun. 

Most solar telescopes exhibit a “sweet spot” in their field of view where subtle prominences pop into clearer view and the larger prominences show more contrast and detail. Experimentally moving the Lunt LS35T/Ha Deluxe around so that the Sun’s limb and prominences move to different parts of the field will soon reveal where your particular scope’s “sweet spot” is located.

Focal Length:
This is the length of the effective optical path of a telescopeor eyepiece (the distance from the main mirror or lens where the lightis gathered to the point where the prime focus image is formed). Focallength is typically expressed in millimeters.

The longer the focallength, the higher the magnification and the narrower the field of viewwith any given eyepiece. The shorter the focal length, the lower themagnification and the wider the field of view with the same eyepiece.

Focal Ratio:
This is the ‘speed’ of a telescope’s optics, found by dividing the focal length by the aperture. The smaller the f/number, the lower the magnification, the wider the field, and the brighter the image with any given eyepiece or camera.

Fast f/4 to f/5 focal ratios are generally best for lower power wide field observing and deep space photography. Slow f/11 to f/15 focal ratios are usually better suited to higher power lunar, planetary, and binary star observing and high power photography. Medium f/6 to f/10 focal ratios work well with either.

An f/5 system can photograph a nebula or other faint extended deep space object in one-fourth the time of an f/10 system, but the image will be only one-half as large. Point sources, such as stars, are recorded based on the aperture, however, rather than the focal ratio – so that the larger the aperture, the fainter the star you can see or photograph, no matter what the focal ratio.

This is the ability of a telescope to separate closely-spaced binary stars into two distinct objects, measured in seconds of arc. One arc second equals 1/3600th of a degree and is about the width of a 25-cent coin at a distance of three miles! In essence, resolution is a measure of how much detail a telescope can reveal. The resolution values on our website are derived using the Dawes’ limit formula.

Dawes’ limit only applies to point sources of light (stars). Smaller separations can be resolved in extended objects, such as the planets. For example, Cassini’s Division in the rings of Saturn (0.5 arc seconds across), was discovered using a 2.5” telescope – which has a Dawes’ limit of 1.8 arc seconds!

The ability of a telescope to resolve to Dawes’ limit is usually much more affected by seeing conditions, by the difference in brightness between the binary star components, and by the observer’s visual acuity, than it is by the optical quality of the telescope.

3.31 arc seconds
This is the diameter of the light-gathering main mirror or objective lens of a telescope. In general, the larger the aperture, the better the resolution and the fainter the objects you can see.
The weight of this product.
3 lbs.
1 year
There are currently no Cloudy Nights reviews associated with this product

User Ratings/Reviews from our Customers (
Overall Product Rating: AstronomicsAstronomicsAstronomicsAstronomicsAstronomics(0.00)   # of Ratings: 0   (Only registered customers can rate)

We haven't recommended any accessories for this product quite yet... check back soon or call one of our experts (1-405-364-0858).
  • Helical focuser
  • Dust cover
  • 1.25” star diagonal with integral 6mm blocking filter
  • TeleVue Sol-Searcher finder
  • Mounting rings and block with 1/4"-20 thread mounting holes
  • 10mm 1.25" Lunt Solar eyepiece
No documents have been associated with this product.
No videos have been associated with this product.
There are currently no formulas associated with this product
Lunt Solar Systems - LS35T/Ha 35mm f/11.4 solar refractor deluxe package

Click icon(s) below & hover image above for zoom

Lunt Solar Systems - LS35T/Ha 35mm f/11.4 solar refractor deluxe package
   · No ratings/reviews   Only registered users can submit ratings - Register Here
Our Product #: L35TPAK
Manufacturer Product #: LS35THaDX
Price: $749.00
$673.00 On Sale  FREE ground shipping - Click for more info
Congratulations. Your order qualifies for free ground shipping within the 48 contiguous United States.

 E-mail this product to a friend E-mail this product to a friend

Your Email:  
Your Friend's Email:  
Confirm Friend's Email:  

  200 characters or less

An email containing a link to this product has been sent to the email address you provided.

Clear Skies!

 Have a question? Do you have a question about this product?
 Found a better price? Found a lower price? Click to let us know... or call 800-422-7876 before you buy.

If you’ve found a lower delivered price on this product, let us know about it below. We’ll do our best to meet or beat that price and will get back to you within one business day with our best offer. Thanks for giving us the opportunity to give you a better deal.

Your Name:  
From Who:  
Context:  Magazine AdOnline
Website Address:  
Cut and paste the web address into the box above
Your Email:  
Confirm Email:  

We’ll do our best to meet or beat that price and will get back to you within one business day with our best offer. Thanks for giving us the opportunity to give you a better deal.

Clear skies,

This economical and lightweight Lunt 35mm Deluxe solar telescope package provides detailed Hydrogen-alpha images of explosive and ever-changing prominences leaping from the limb of the Sun, plus sunspots and surface features . . .

. . . our 34th year